"We used to do terrible things," Timberlake, 30, says in an interview airing Thursday on The Ellen DeGeneres Show. "We stole a golf cart. And we're like, 'Yeah, man. We're stealing a golf cart.' But meanwhile, you know what? It's like on a backlot. There's just golf carts everywhere."

"So, we stole the golf cart, and we drove into MGM Studios, which is totally illegal by the way," says Timberlake. "I was like, 'What you want to do, thug?' And [Ryan] was like, 'I don't know, cuz.' Because that's definitely how we talked."

"I was like, 'I don't know man. I'm in the mood for some vanilla.' He was like, 'I'm in the mood for some chocolate.' So, we went and got milkshakes."

Timberlake and Gosling actually lived together for six months when they were about 10, as Gosling's mother had to keep her job in Canada – and Timberlake's mother became Ryan's temporary guardian.

"We were probably a little closer that the rest of the kids," says Timberlake, "just because we had to share a bathroom."

With their busy schedules, Timberlake says it's hard to keep up with Gosling these days. But he admires his work. "He's always been that charismatic and that talented," Timberlake says. "He's unbelievable. I think one of the best actors of our generation."